This invention relates to an improved retaining wall construction and, more particularly, to a retaining wall construction comprised of modular blocks, in combination with tie-back and/or mechanically stabilized earth elements and compacted particulate or soil.
In U.S. Pat. No. 3,686,873 and U.S. Pat. No. 3,421,326, Henri Vidal discloses a constructional work now often referred to as a mechanically stabilized earth structure. The referenced patents also disclose methods for construction of mechanically stabilized earth structures such as retaining walls, embankment walls, platforms, foundations, etc. In a typical Vidal construction, particulate earthen material interacts with longitudinal elements such as elongated steel strips positioned at appropriately spaced intervals in the earthen material. The elements are generally arrayed for attachment to reinforced precast concrete wall panels and, the combination forms a cohesive embankment and wall construction. The longitudinal elements, which extend into the earthen work, interact with compacted soil particles principally by frictional interaction and thus mechanically stabilize the earthen work. The longitudinal elements may also perform a tie-back or anchor function.
Various embodiments of the Vidal development have been commercially available under various trademarks including the trademarks, REINFORCED EARTH embankments and RETAINED EARTH embankments. Moreover, other constructional works of this general nature have been developed. By way of example and not by way of limitation, Hilfiker in U.S. Pat. No. 4,324,508 discloses a retaining wall comprised of elongated panel members with wire grid mats attached to the backside of the panel members projecting into an earthen mass.
Vidal, Hilfiker and others generally disclose large precast, reinforced concrete wall panel members cooperative with strips, mats, etc. to provide a mechanically stabilized earth construction. Vidal, Hilfiker and others also disclose or use various shapes of wall panel members. It is also noted that in constructions disclosed by Vidal and Hilfiker, the elements interactive with the compacted earth or particulate behind the wall panels or blocks, are typically rigid steel strips or mats which rely upon friction and/or anchoring interaction with the particulate, although ultimately, all interaction between such elements and the earth or particulate is dependent upon friction.
It is sometimes difficult or not practical to work with large panel members like those disclosed in Vidal or Hilfiker inasmuch as heavy mechanical lifting equipment is often required to position such panels. In such circumstances, smaller blocks rather than panels may be used to define the wall. Forsberg in U.S. Pat. No. 4,914,876 discloses the use of smaller retaining wall blocks in combination with flexible plastic netting as a mechanically stabilizing earth element to thereby provide a mechanically stabilized earth retaining wall construction. Using flexible plastic netting and smaller, specially constructed blocks arranged in rows superimposed one upon the other, reduces the necessity for large or heavy mechanical lifting equipment during the construction phase of such a wall.
Others have also suggested the utilization of facing blocks of various configurations with concrete anchoring and/or frictional netting material to build an embankment and wall. Among the various products of this type commercially available is a product offered by Rockwood Retaining Walls, Inc. of Rochester, Minn. and a product offered by Westblock Products, Inc. and sold under the tradename, Gravity Stone. Common features of these systems appear to be the utilization of various facing elements in combination with backfill, wherein the backfill is interactive with plastic or fabric reinforcing and/or anchoring means which are attached to the facing elements. Thus, there is a great diversity of such combinations available in the marketplace or disclosed in various patents and other references.
Nonetheless, there has remained the need to provide an improved system utilizing anchoring and/or frictional interaction of backfill and elements positioned in the backfill wherein the elements are cooperative with and attachable to facing elements, particularly blocks which are smaller and lighter than large facing panels such as utilized in many installations. The present invention comprises an improved combination of elements of this general nature and provides enhanced versatility in the erection of retaining walls and embankments, as well as in the maintenance and cost of such structures.